Hi Leah -
I know how scared you are, but you need to have this lump checked even if only the size of a pea. I was only 31 when I was diagnosed with Stage IIa Invasive Ductal Carcinoma. 3 years later I had a chest wall recurrence even though I had a modified radical mastectomy. I had orginally thought I had a clogged milk duct as I had found it after a miscarriage and my lump was in the 12 o'clock position just above my nipple.
There are chances that this lump is absolutely nothing, but there is also a slim chance it is something and only a doctor can tell you what it is by way of a mammogram and/or ultrasound. Cancer is not just for women over 40 - Look at Christina Applegate, Kylie Minogue, Sheryl Crow - they were all in their 30's. Good breast health, exams and mammograms are extremely important no matter what the age is. If you go to your doctor and it turns out to be just a cyst, at least you will have a baseline mammo to be used in the future and track any changes. Either way you CAN be ok. Early detection is key!
Best of luck! Please keep us posted!
Angi